I've just received an email stating that you should fill freezer baggies half full and put 4 - 5 pennies in them and hang them up. Flies and wasps don't like them - I guess they think that there other flies staring back at them. Other people have said that it works. Hope this helps.

I saw a hint some where that you can fill a ziplock bag with water and put 4 or 5 pennies in and zip it closed and hang it where you have a fly problem. I think a quart size would be large enough. I have not tried this yet, I would like to know if it really works.